Technical Abstract:
Two groups of poults that differed only in day of placement (Group A = Day of Hatch, Group B = Day after Hatch) were reared together. Sequential body weights and fecal samples were obtained and all birds that died or were culled were necropsied. Samples were examined for enteropathogens and skeletal lesions were cultured for Mycoplasma iowae. Day of placement had effects on growth, uniformity, Salmonella colonization, and pattern and causes of mortality and culling. It did not affect total mortality, E. coli colonization, or enteric virus infection. E. coli colonized poults prior to placement and isolates were highly resistant to antimicrobials. Campylobacter and parasite infections did not occur. M. iowae was isolated infrequently. Group A poults were consistently heavier, had better uniformity, less Salmonella colonization, and greater losses from culling and musculoskeletal diseases. Mortality and cardiovascular diseases occurred more frequently in Group B poults.